Genomic characterization and probiotic potential assessment of an exopolysaccharide-producing strain Pediococcus pentosaceus LL-07 isolated from fermented meat.

BACKGROUND: The genomic information available for Pediococcus pentosaceus is primarily derived from fermented fruits and vegetables, with less information available from fermented meat. P. pentosaceus LL-07, a strain isolated from fermented meat, has the capability of producing exopolysaccharides (EPS). To assess the probiotic attributes of P. pentosaceus LL-07, we conducted whole-genome sequencing (WGS) using the PacBio SequelIIe and Illumina MiSeq platforms, followed by in vitro experiments to explore its probiotic potential. RESULTS: The genome size of P. pentosaceus LL-07 is 1,782,685 bp, comprising a circular chromosome and a circular plasmid. Our investigation revealed the absence of a CRISPR/Cas system. Sugar fermentation experiments demonstrated the characteristics of carbohydrate metabolism. P. pentosaceus LL-07 contains an EPS synthesis gene cluster consisting of 13 genes, which is different from the currently known gene cluster structure. NO genes associated with hemolysis or toxin synthesis were detected. Additionally, eighty-six genes related to antibiotic resistance were identified but not present in the prophage, transposon or plasmid. In vitro experiments demonstrated that P. pentosaceus LL-07 was comparable to the reference strain P. pentosaceus ATCC25745 in terms of tolerance to artificial digestive juice and bile, autoaggregation and antioxidation, and provided corresponding genomic evidence. CONCLUSION: This study confirmed the safety and probiotic properties of P. pentosaceus LL-07 via complete genome and phenotype analysis, supporting its characterization as a potential probiotic candidate.

A comprehensive assessment of the antimicrobial and immunomodulatory effects of frequently consumed fermented foods: insights in the management of COVID-19.

COVID-19, which is caused by the novel coronavirus SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), is the deadliest outbreak of this millennium. Despite adopting several precautionary strategies and guidelines, COVID-19 has spread rapidly, and the number of cases is still in escalation across the world. The various immune-boosting drugs with severe side effects and the vaccines approved after negotiated clinical trials have been struggling to cope with the emergence of new variants of the virus. Nevertheless, given a large number of asymptomatic cases, a high magnitude of recovery rate, and a relatively higher prevalence of morbidity and mortality among immunologically compromised individuals, those affected by an illness, and the elderly, it appears that a healthy microbiome and the associated immune responses are the key factors for survival. Incidentally, the consumption of traditionally popular and nutritious fermented foods, which are composed of biologically functional ingredients and several health-promoting probiotics, offers promising health benefits through the improvement of the immune system in general. Given the progress in functional food research, it has become crucial to understand the impact of a healthy microbiome and the immunomodulatory roles of fermented foods on the battles to combat infectious diseases. Based on the evidence of the impact of probiotics-based fermented foods, the beneficial roles of a few frequently consumed fermented foods in the management of various infections have been resolutely discussed in the present study, with a focus on their antagonistic and immune-modulating effects in the context of the current COVID-19 pandemic.

Integrated genome-based assessment of safety and probiotic characteristics of Lactiplantibacillus plantarum PMO 08 isolated from kimchi.

Lactiplantibacillus plantarum PMO 08 has been used as a probiotic starter culture for plant-based fermented beverages, with various health-promoting effects such as cholesterol-lowering and anti-inflammatory activities. This study aimed to analyze the genome sequence of Lp. plantarum PMO 08 and identify its safety and probiotic characteristics at the genomic level. For this, complete genome sequencing was conducted to investigate the genes associated with risk and probiotic characteristics by using Pacbio combined with Illumina HiSeq. This bacterial strain has one circular chromosome of 3,247,789 bp with 44.5% G + C content and two plasmids of 50,296 bp with 39.0% G + C content and 19,592 bp with 40.5% G + C content. Orthologous average nucleotide identity analysis showed that PMO 08 belongs to the Lp. plantarum group with 99.14% similarity to Lp. plantarum WCFS1. No deleterious genes were determined in the virulence factor analysis, and no hemolysin activity or secondary bile salt synthesis were detected in vitro test. In the case of antibiotic resistance analysis, PMO 08 was resistant to ampicillin in vitro test, but these genes were not transferable. In addition, the strain showed same carbohydrate utilization with Lp. plantarum WCFS1, except for mannopyranoside, which only our strain can metabolize. The strain also harbors a gene for inositol monophosphatase family protein related with phytate hydrolysis and have several genes for metabolizing various carbohydrate which were rich in plant environment. Furthermore, in probiotic characteristics several genes involved in phenotypes such as acid/bile tolerance, adhesion ability, and oxidative stress response were detected in genome analysis. This study demonstrates that Lp. plantarum PMO 08 harbors several probiotic-related genes (with no deleterious genes) and is a suitable probiotic starter for plant-based fermentation.

Safety Assessment Systems for Microbial Starters Derived from Fermented Foods.

Microorganisms involved in food fermentation not only improve the aroma and taste of the food, but also enhance its preservation. Thus, they are added as starter cultures to boost the final product quality of commercial fermented foods. Although these microorganisms originate from fermented foods and have a long history of consumption, the European Union recently applied the concept of Qualified presumption of Safety (QPS), which is a safety evaluation system for microorganisms used in food or feed in Europe. The QPS system is a species-level safety system and shares results with the European Novel Food System, a strain-level safety evaluation system. In the United States, microorganisms added to fermented foods are considered as food additives or Generally Recognized as Safe substance. In Korea, food microbe lists are presented at the species level. Moreover, the nation has established a strain-oriented evaluation system that applies temporary safety evaluation methods for food raw materials as well as new raw materials. However, when it comes to microorganisms isolated from traditional fermented foods and other fermented food products, there is no definition of the term "species," and there is a lack of an evaluation system at the species level. Therefore, such an evaluation system for microbial species used in Korean fermented foods is necessary.

Assessment of probiotic and technological properties of Bacillus spp. isolated from Burkinabe Soumbala.

BACKGROUND: Soumbala is a highly loved alkaline traditional fermented food condiment in Burkina Faso. It harbors various microbiota dominated by fermentative Bacillus spp. as functional microorganism with little confirmed health-promoting properties. METHODS: The present study aimed to evaluate six Bacillus strains previously isolated and identified from soumbala. These strains were selected as presumptively safe bacteria for probiotic and technological characteristics. These strains were assessed for in vitro probiotic criteria (tolerance to acidic pH, gastric juice, 0.3% (m/v) bile salts, intestinal juice and 0.4% (w/v) phenol, cell surface hydrophobicity, auto-aggregation capacity, antimicrobial activity against foodborne pathogens, antibiotic susceptibility and biofilm production) and technological properties, including protease, amylase, lipase, and tannase activity, as well as poly-γ-glutamic acid (PGA) production and thermo-tolerance. RESULTS: All tested Bacillus strains (B54, F20, F24, F21, F26 and F44) presented variable relevant probiotic properties (good tolerance to pH 2 and pH 4, gastric juice, bile salts, intestinal juice and phenol), with marked differences in hydrophobicity and auto-aggregation capacity ranging from 73.62-94.71% and 49.35-92.30%, respectively. They exhibited a broad spectrum of activity against foodborne pathogens depending on target pathogen, with the highest activity exhibited by strain F20 (29.52 mm) against B. cereus 39 (p < 0.001). They also showed good biofilm production as well as variable hydrolytic enzyme activities, including protease (43.00-60.67 mm), amylase (22.59-49.55 mm), lipase (20.02-24.57 mm), and tannase (0-10.67 mm). All tested Bacillus strains tolerated temperature up to 50 °C, while only strains F26 and F44 showed the best PGA production. CONCLUSION: Overall, the tested cultures exhibiting potential probiotic and technological characteristics; particularly B. cereus F20, B. benzoevorans F21, B. cabrialessi F26, and B. tequilensis F44 could be a source of probiotic-starters of commercial interest in the production of high-quality soumbala.

Safety assessment of white colony-forming yeasts in kimchi.

White colony-forming yeasts (WCFYs) have been reported to form a white colony on the surface of kimchi, resulting in the deterioration of kimchi sensory quality. However, toxicity of WCFY has rarely been studied. Thus, to evaluate the safety of WCFY (i.e., Kazachstania servazzii, Candia sake, and Pichia kudriavzevii), we conducted cell and animal experiments as well as genomic analysis. In vitro studies indicated that WCFY did not induce cytotoxic responses such as lactate dehydrogenase release, excessive oxidative stress, and mitochondrial damage at concentrations of up to 2.5 × 105 CFU/mL in human intestinal and liver cells. In animal studies using rats (single-dose and 14-day repeated-dose oral toxicity studies), WCFY did not induce death, clinical signs of toxicity, histological alterations of the liver, or increases in the expression of pro-inflammatory cytokines nor cytochrome P450-2E1 in liver tissue at concentrations of up to 5 × 108 CFU/head/day. Genomic analysis revealed that P. kudriavzevii did not harbor genes related to toxicity and antimicrobial resistance. Taken together, our data suggest that exposure to WCFY through kimchi intake did not induce toxic response in the Caco-2, HepG2, and Sprague-Dawley rats. The current work provides evidence for the safety of accidental major WCFY ingestion via kimchi.

Quantification of heavy metals and health risk assessment in Sichuan pickle.

Sichuan pickle is one of popular traditional fermented foods in China. However, the contamination of heavy metals in Sichuan pickle, particularly home-made Sichuan pickle and aged pickle brine, is little known. Therefore, the content of trace (Cr, Cu, and Zn) and toxic elements (As, Pb, and Cd) in Sichuan industrial pickle (SIP), Sichuan home-made pickle (SHP), and aged pickle brine collected from local markets and families in Sichuan province, respectively, was detected by inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) and the health risk was assessed by target hazard quotients including target hazard quotient (THQ) and total target hazard quotient (TTHQ). Consequently, the mean concentrations of Cr, Cu, Zn, As, Pb, and Cd were 0.122, 0.540, 2.516, 0.023, 0.015, and 0.106 mg/kg in SIP and 0.071, 0.364, 2.698, 0.014, 0.015, and 0.289 mg/kg in SHP, respectively, lower than the maximum allowable concentrations set by Chinese regulations, except for Cr and Cd in few samples. Principal component analysis of the heavy metal content could obviously distinguish between SIP and SHP. The content of As, Pb, and Cd in leaf pickles was significantly higher than that in pickles fermented with other types of vegetables. A significant enrichment of heavy metals in aged pickle brine over 10 years was observed, but pickle jars had no significant effect on heavy metal content in aged pickle brine. The intake of heavy metals through daily consumption of SIP and SHP was at a safe level, whereas the TTHQ of leaf pickle was 1.006, indicating a potential health risk. In conclusion, this study provided fundamental data for food safety assurance of Sichuan pickle. PRACTICAL APPLICATION: Sichuan pickle is one of popular traditional fermented foods in China. In the present study, we investigated the contamination of heavy metals in Sichuan pickles by detecting the content of Cr, Cu, Zn, As, Cd, and Pb in Sichuan industrial pickle, Sichuan home-made pickle, and aged pickle brine, and estimated the health risk to local residents. This study can provide a reference for the safety risk of Sichuan industrial and home-made pickle in terms of heavy metal contamination, and enhance the food safety in the processing, production, and consumption of Sichuan pickle in local families and pickle industry.

Fermented foods: Availability, cost, ingredients, nutritional content and on-pack claims.

INTRODUCTION: Fermented foods have been consumed for millennia and commercially-produced variants are now available in the food supply. The present study aimed to investigate the availability, cost, ingredients, nutritional content and on-pack claims of commercially-available fermented foods in the UK. METHODS: All products from seven categories of commercially-available fermented foods were systematically identified at eight national supermarket chains in the UK. Data were extracted from manufacturer and retailer websites and were compared between categories using a Kruskal-Wallis test and Fisher's exact test. RESULTS: In total, 143 fermented foods were identified, with kombucha (41, 28.7%), kefir drinks (32, 22.4%), sauerkraut (22, 15.4%) and kefir yoghurts (21, 14.7%) being most common. The number of products sold at each retailer differed between categories (p = 0.016), and was greatest for kefir drink (median = 7.0, interquartile range [IQR] = 9.0), kombucha (median = 5.5, IQR = 11.5) and kefir yoghurts (median = 5.0, IQR = 8.5). Kombucha (£1.99 per serving) and kefir drinks (£1.26 per serving) were the most expensive fermented foods and sauerkraut (£0.66 per serving) and miso (£0.20 per serving) were the least expensive. Energy, fat, saturated fat, sugar, protein and salt content varied between fermented foods (p < 0.001). Nutrition claims were made on 72 (50.3%) products, the total number of cultures was labelled on 29 (20.3%), specific strains were named on 53 (37.1%) and bacteria-related benefits were promoted on 39 (27.3%) products. CONCLUSIONS: Commercially-produced fermented foods are widely available in the UK but are diverse in their cost, nutritional content, ingredients and use of on-pack claims. Consumers should be aware of these variations given the limited evidence of functional benefits from controlled human trials.

Contamination characteristics and risk assessment of aflatoxins in homemade soybean paste, a traditional fermented soybean food, in South Korea.

Soybean paste is manufactured through microbial fermentation and may become contaminated with aflatoxins. Herein, we conducted nationwide large-scale monitoring (n = 1436) over three years (2018-2020) to investigate aflatoxin levels according to geographic, demographic, manufacturing, quality factors, and risk characteristics of homemade soybean paste produced through fermentation. The mean level of total aflatoxins was 5.88 µg/kg (range, 0.01-281.92), with the most common contaminating type being the B type. Aflatoxin levels significantly differed according to the region, age of the manufacturer, type of starter used, and the amino-type nitrogen content and pH of the homemade soybean paste (p < 0.05). Aflatoxin levels was significantly higher when starters were manufactured using the traditional method (inoculation with a naturally occurring strain in the surrounding environment). The aflatoxin exposure level estimated through the average intake of homemade soybean paste in all age groups was 0.1012 ng/kg body weight/day. The risk assessment for the genotoxic and carcinogenic potential of aflatoxins using the margin of exposure approach revealed values of 3705-3954 for average intake of homemade soybean paste, indicating public health concern. These results suggest that follow-up studies and safety management strategies are needed to reduce aflatoxin levels in homemade soybean paste.

Assessing levels of traditionality and naturalness depicted on labels of fermented meat products in the retail: Exploring relations with price, quality and branding strategy.

Food labelling is a tool to inform consumers about the specifications and characteristics of a product. Additionally, labels display information about traditionality and naturalness, of which the meaning is highly subjective. There is a paucity of research examining attributes both of tradition and naturalness. In this study, traditionality was assessed by a model that included temporal, geographical, know-how, and cultural components. Naturalness was evaluated based on bio/organic elements, 'free-from' claims, and natural ingredients. Therefore, a content analysis tool was developed to analyze and score labels of fermented meat products, which generated insights in the key label characteristics of tradition and naturalness. The degree of tradition and naturalness was the average of their subdimensions which were scored based on the displayed elements. A higher degree of tradition and naturalness was linked to higher prices. Fermented meat labels were found to be strongly embedded in 'authenticity', and less in naturalness, an element more attractive for private labels than for branded products.

Risk management tool to define a corrective storage to enhance Salmonella inactivation in dry fermented sausages.

The resistance of Salmonella to the harsh conditions occurring in shelf-stable dry fermented sausages (DFS) poses a food safety challenge for producers. The present study aimed to model the behaviour of Salmonella in acid (with starter culture) and low-acid (without starter culture) DFS as a function of aw and storage temperature in order to build a decision supporting tool supporting the design of a corrective storage strategy to enhance the safety of DFS. Salmonella spp. were inoculated in the raw meat batter at ca. 6 Log cfu/g with a cocktail of 3 strains (CTC1003, CTC1022 and CTC1754) just before mixing with the other ingredients and additives. After stuffing, sausages were fermented and ripened following industrial processing conditions. Different drying-times were applied to obtain three batches with different aw (0.88, 0.90 and 0.93). Afterwards, DFS were stored at 4, 8, 15 and 25 °C for a maximum of three months and Salmonella spp. were periodically enumerated. The Weibull model was fitted to Log counts data to estimate inactivation kinetic parameters. The impact of temperature and aw on the primary inactivation parameters was evaluated using a polynomial equation. The results of the challenge tests showed that Salmonella spp. levels decreased during storage at all the assayed conditions, from 0.8 Log (in low-acid DFS at 4 °C) up to 6.5 Log (in acid DFS at 25 °C). The effect of both aw and temperature was statistically significant. Delta (δ) parameter decreased by decreasing aw and increasing temperature, while the shape (p) parameter ranged from above 1 (concave) at 10 °C to below 1 at 25 °C (convex). A common secondary model for the p parameter was obtained for each type of DFS, acid and low-acid, indicating that acidification during the production of DFS affected the time for the first Log reduction (δ) during the subsequent storage, but not the overall shape (p parameter) of the inactivation. The developed models covered representative of real conditions, such as Salmonella contamination in the raw materials and its adaptation to the harsh processing conditions. The good predictive performance shown when applying the models to independent data (i.e. up to 80% of the predictions within the 'Acceptable Simulation Zone' for acid sausages) makes them a suitable and reliable risk management tool to support manufacturers to assess and design a lethality treatment (i.e. corrective storage) to enhance the Salmonella inactivation in the product before DFS are released to the market.

Assessment of exopolysaccharides, bacteriocins and in vitro and in vivo hypocholesterolemic potential of some Egyptian Lactobacillus spp.

Lactobacilli probiotics have been suggested to reduce cholesterol with low side effects to host. Bacteriocins and exopolysaccharides (EPSs) production are two meaningful examples of functional applications of lactobacilli in the food industry. Eight Lactobacillus strains were isolated from some Egyptian fermented food and tested for their probiotic properties. Analysis of the monosaccharide composition by thin layer chromatography showed the presence of glucose, galactose and unknown sugar. The main functional groups of EPSs were elucidated by Fourier-Transform Infrared Spectroscopy. Their fermentation cultures displayed powerful antioxidant activities extending from 97.5 to 99%, 40-75% for their EPSs and free cells, respectively, and exhibited in vitro cholesterol downgrading from 48 to 82% and 72 to 91% after 48 and 120 h, respectively. Their EPSs showed good anticancer activities against carcinoma cells with low IC50 values for HCT-116, PC-3 and HepG-2 cells. To the best of our knowledge, there have been no previous reports on the potential of Lactobacillus EPSs activity against PC-3. The selected strains, L. plantarum KU985433 and L. rhamnosus KU985436 produced two different bacteriocins as detected by gel permeation chromatography with good antimicrobial activities. In vivo study demonstrated that feeding Westar rats with fermented milk exhibited greater cholesterol, LDL and blood triglyceride reduction for both strains. Whereas, HDL was increased by about 43 and 38%, respectively, and the atherogenic indices decreased.

In Vitro Assessment of Probiotic Potential of Saccharomyces Cerevisiae DABRP5 Isolated from Bollo Batter, a Traditional Goan Fermented Food.

Bollo is a traditional Goan fermented food in which coarse wheat/wheat and finger millet is leavened with toddy. We here isolated 42 yeast strains from Bollo batter. Initial screening of the isolates with probiotic properties yielded four yeast isolates (DABRP1, DABRP2, DABRP5 and DABRP12). These isolates exhibited tolerance to high bile salt concentration and acidic pH and resistance to various antibiotics, which indicated their probiotic nature. All these yeast isolates were identified as Saccharomyces cerevisiae through D1D2-LSU-rDNA sequencing. These yeast isolates also showed higher percent hydrophobicity towards chloroform followed by n-hexadecane and o-xylene indicating their mucosal surface-adhesive property. To evaluate the safety of the isolates for them to be called as generally recognized as safe, the pathogenic behavior of the isolates determined through the in vitro hemolysis assay and evaluation of DNase and gelatinase activities. None of the isolates exhibited hemolysis or produced DNase or gelatinase and thus were considered potentially safe. In terms of beneficial effects, the most potent isolate S. cerevisiae DABRP5 showed antibacterial activity against the test pathogens. It also showed excellent antioxidant activity with DPPH free radical scavenging activity of 68.85 ± 0.69%, anti-inflammatory activity with 60.39 ± 0.34% inhibition of protein denaturation, and antidiabetic activity with 71.75 ± 0.45% inhibition of α-amylase activity. The isolate produced α-amylase, lipase, and ß-galactosidase. The probiotic potential of the isolate S. cerevisiae DABRP5 was similar to that of the reference strain (Saccharomyces boulardii CNCM I-745) used in this study. The results thus indicate that yeast isolates from Bollo batter have probiotic potential.

Assessment of human norovirus inhibition in cabbage kimchi by electron beam irradiation using RT-qPCR combined with immunomagnetic separation.

Cabbage Kimchi, a traditional Korean fermented food, has occasionally been related to acute gastroenteritis caused by human norovirus (HuNoV). The present study examined the inhibitory effects of electron beam (e-beam) irradiation (1, 3, 5, 7, and 10 kGy) on HuNoV GII.4 in suspension or cabbage Kimchi using reverse transcription quantitative polymerase chain reaction combined with immunomagnetic separation (IMS/RT-qPCR). In addition, physicochemical and sensorial analyses were conducted to assess any change in the quality of cabbage Kimchi following e-beam irradiation. Following e-beam irradiation at 1 to 10 kGy, HuNoV significantly decreased to 0.28 to 2.08 log10 copy number/mL in suspension (P < 0.05). HuNoV levels in cabbage Kimchi were also significantly reduced to 0.26 to 1.57 log10 copy number/mL following irradiation with 1 to 10 kGy (P < 0.05) compared to positive control (6.0 log10 copy number/mL). The D-values for 1 log10 reduction (90% inhibition) of HuNoV in suspension and cabbage Kimchi were 4.94 and 6.96 kGy of e-beam, respectively. The pH and acidity in the irradiated cabbage Kimchi were 4.41 to 4.58 and 0.61% to 0.71%, respectively, indicating that e-beam did not affect the optimal pH or acidity. Although a slight increase of greenness was observed in the leaf portion of cabbage Kimchi irradiated with 7 to 10 kGy of e-beam, this color change was minimal and went undetected by panelists in the sensorial evaluation. The five properties of sensorial quality assessed were no different in the irradiated Kimchi sample compared with the control sample (nonirradiated cabbage Kimchi). Therefore, this study suggests that ≥6.96 kGy of e-beam could be applied in the cabbage Kimchi industry to obtain >90% of HuNoV without affecting the quality. PRACTICAL APPLICATION: As the most representative food in Korea, Kimchi needs the sanitation technology that can inhibit viral infection. Our findings suggest that e-beam irradiation can be used to reduce HuNoV effectively in Kimchi without changes in sensorial quality.

Gas chromatography-mass spectrometry-based metabolomics analysis of metabolites in commercial and inoculated pickles.

BACKGROUND: Starter cultures are nowadays more and more used to make inoculated pickles (IPs), but it remains unclear whether there are differences in flavors between IPs and naturally fermented pickles. In this study 16 commercial pickles (CPs) produced by spontaneous fermentation method were purchased from markets in Sichuan province and Chongqing. Ten strains of three lactic acid bacteria species - Lactobacillus plantarum, Leuconostoc mesenteroides and Pediococcus ethanolidurans - were selected as single starter cultures to produce IPs. RESULTS: Differences in flavor components between the CPs and IPs were monitored using a combination of gas chromatography-mass spectrometry and multivariate statistical methods. Higher levels of nonvolatile substances such as glucose, fructose, tagatose, sucrose, lactic acid and mannitol were detected in most IPs than in the CPs. The values of flavor characteristics such as sweetness, umami and astringency, which were correlated positively with consumers' overall preferences for pickles, were higher in the IPs than in the CPs. Volatile compounds such as geranyl acetate, dimethyl trisulfide, eucalyptol and linalool were distinguished as the main compounds that contributed to the flavor characteristics of the CPs. In addition to dimethyl trisulfide, dimethyl disulfide was also an odor contributor to the IPs. CONCLUSIONS: The CPs and IPs had different flavor characteristics, especially in the composition and content of volatile components, and the inoculation method reflected some fermentation advantages, which could reduce the bitterness and increase umami and lead to a higher score of sensory preference. This will be helpful for industrial production. © 2020 Society of Chemical Industry.

Fermented foods in a global age: East meets West.

Fermented foods and alcoholic beverages have long been an important part of the human diet in nearly every culture on every continent. These foods are often well-preserved and serve as stable and significant sources of proteins, vitamins, minerals, and other nutrients. Despite these common features, however, many differences exist with respect to substrates and products and the types of microbes involved in the manufacture of fermented foods and beverages produced globally. In this review, we describe these differences and consider the influence of geography and industrialization on fermented foods manufacture. Whereas fermented foods produced in Europe, North America, Australia, and New Zealand usually depend on defined starter cultures, those made in Asia and Africa often rely on spontaneous fermentation. Likewise, in developing countries, fermented foods are not often commercially produced on an industrial scale. Although many fermented products rely on autochthonous microbes present in the raw material, for other products, the introduction of starter culture technology has led to greater consistency, safety, and quality. The diversity and function of microbes present in a wide range of fermented foods can now be examined in detail using molecular and other omic approaches. The nutritional value of fermented foods is now well-appreciated, especially in resource-poor regions where yoghurt and other fermented foods can improve public health and provide opportunities for economic development. Manufacturers of fermented foods, whether small or large, should follow Good Manufacturing Practices and have sustainable development goals. Ultimately, preferences for fermented foods and beverages depend on dietary habits of consumers, as well as regional agricultural conditions and availability of resources.

In vivo and in vitro safety evaluation of fermented Citrus sunki peel extract: acute and 90-day repeated oral toxicity studies with genotoxicity assessment.

BACKGROUND: Citrus sunki Hort. ex Tanaka peel has been traditionally used as an ingredient in folk medicine due to its therapeutic effects on promotion of splenic health and diuresis as well as relief of gastrointestinal symptoms. Although a growing interest in health-promoting natural products and the development of highly concentrated products have facilitated consumption of C. sunki peel, its safety assessment has not been explored, posing a potential health risk. In this study, we carried out a series of systemic and genetic toxicity tests on fermented C. sunki peel extract (FCPE) to provide the essential information required for safe use in human. METHODS: We conducted acute and 90-day repeated oral toxicity studies in Sprague-Dawley rats to evaluate systemic toxicity, and three genotoxicity assays to measure bacterial mutation reversion, cellular chromosome aberration and in vivo micronucleus formation. RESULTS: Single oral administration of FCPE did not cause any clinical signs and lethality in all animals, establishing LD50 to be over 2000 mg/kg BW. Repeated administration of up to 2000 mg/kg BW FCPE for 90 days revealed no test substance-related toxicity as demonstrated in analysis of body weight gain, food/water intake, blood, serum biochemistry, organ weight and histopathology, collectively determining that the no-observable-adverse-effect-level of FCPE is over 2000 mg/kg BW. In addition, we detected no mutagenicity and clastogenicity in FCPE at 5000 µg/plate for the in vitro assays and 2000 mg/kg BW for the in vivo micronucleus test. CONCLUSION: FCPE did not cause systemic and genetic toxicity in our model systems at the tested dose levels. These results suggest a guideline for safe consumption of C. sunki peel in human.

Assessment of commercial companion animal kefir products for label accuracy of microbial composition and quantity.

Kefir is a fermented beverage containing yeast and bacteria produced by the fermentation of water or milk with kefir grains. Lack of regulation for probiotic-containing fermented food sold for companion dogs and cats creates the potential for misreporting on viable microbial counts, taxonomy, and label claims. In this study, the microbiota of six companion animal kefir products were measured quantitatively using standard plating techniques. Microbial composition of these products was also characterized by using high-resolution, long-read amplicon sequencing of the 16S rRNA gene. Five products (83%) listed specific microorganisms, and four products (66%) guaranteed colony forming units (CFU)/g on their label. To enumerate viable lactic acid bacteria (LAB), two lots of each homogenized product were plated upon opening and following 14 d on deMan Rogosa and Sharpe (MRS) agar and incubated under anaerobic and aerobic conditions. Results from point of opening revealed that all commercial kefir products with a guaranteed CFU/g overstated the number of microorganisms present by at least 1 log, with only one product exceeding 1 × 109 CFU/g. Sequencing results demonstrated that none of the labels claiming specific bacterial genera and species on their labels were correct, and all products contained at least three additional bacterial species above the minimum detectable threshold (0.001% relative abundance) that were not disclosed by the manufacturer. In addition to the incorrect viable CFU and bacterial taxonomies, several of the product labels and websites contained a wide range of health claims, none of which are supported by the companion animal literature. Our results demonstrate a low level of accuracy in the labeling of commercial kefir products intended for use in dogs and cats. Regulatory agencies, veterinarians, pet food professionals, and pet owners must scrutinize these products and demand a higher level of accuracy and quality in the future.

Application of commercial kits using DNA-based and immunochemical methods for determination of shrimp allergens in kimchi and its ingredients.

Shrimps cause a significant part of crustacea-related allergies. It is used in processed foods, including fermented Korean foods, such as kimchi. Even low amounts of shrimp allergens can provoke reactions in consumers allergic to shrimp. Accurate food labeling is the most effective means of preventing the consumption of allergenic ingredients. To validate labeling compliance and minimize the risk of cross-contaminations, the effectiveness of methodologies used for the detection of allergens in foods should be compared. Here, seven commercial kits, based on quantitative real-time polymerase chain reaction (PCR) or enzyme-linked immunosorbent assay (ELISA), were assessed for their ability to detect the presence of shrimp allergens in food. Our results showed that SureFood real-time PCR kit and Ridascreen ELISA kit had the highest recovery, whereas five other kits underperformed in the determination of allergen content of kimchi and its ingredients. The variation in recovery among the kits depended on the limit of detection and reactivity to the shrimp allergens, tropomyosin, and sarcoplasmic calcium-binding protein. PRACTICAL APPLICATION: This research confirms the performance of commercial kits to detect the presence of shrimp allergens in kimchi, and demonstrates that the sensitivity of these kits depends on reactivity to the specific shrimp allergenic proteins. These results can be used to food allergy labeling and can be applied by the food industry to develop allergen test kits for fermented foods with improved performance.